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PATENTED FEB. 9, 1904.

E WALKER. STRENGTHBNER FOR VULGANITE ARTIFICIAL TEETH BASES.

APPLICATION FILED OUT. 31, 1903 N0 MODEL} 01 MN 70R.

UNITED STATES Patented February 9, 1904;.

PATENT OFFICE.

ROBERT WALKER, OF LONDON, ENGLAND.

SPECIFICATION forming part of Letters Patent No. 751,582, dated February9, 1904;.

Application filed October 31,1903,

T0 (LZZ w/wnt it may concern:

Be it known that I, ROBERT IVALKER, asubject of the King of GreatBritain, residing at London, England, have invented a certain new anduseful Improvement in Strengtheners for vulcanite Artificial-TeethBases, of which the following is a specification.

The invention relates to strengtheners for the vulcanite bases ofartificial teeth, the ob ject being to provide strengthening means whichwill not work or out their way through the vulcanite covering and yet belight in weight, elastic, and sufficiently strong for the purposerequired.

Strengtheners for vulcanite artificial-teeth bases of various forms areat present in use; but all those that I am aware of either from beingtoo open have a tendency to cut or work through the vulcanite in theirexpansion or contraction when the latter is bent to and fro or in otherconstructions from being too solid they fail to properly interlock orgrip the vulcanite, and hence become separated therefrom.

In the accompanying drawings are illustrated strengtheners for bothupper andlower cases constructed according to my invention.

Figure 1 is a plan lookingupward of an upper-case strengthener; Fig. 2,an under side view of a part of same on an enlarged scale; Fig. 3,asection of Fig. 2 on line 3 3; Fig. 4, a perspective view of astrengthener for a lower case; Fig. 5, an under side view ofa part ofsame on an enlarged scale; Fig. 6, a section of Fig. 5 on line 5 5, andFig. 7 a cross-section of Fig. 5 on line 7 7.

According to my invention I employ a metal strengthening device composedof a metal plate of any suitable thickness, according to the nature ofthe metal, pierced with such a number of openings that it becomes almosta metal fabric, as shown in Figs. 1 to 3, the meshes or portions ofwhich surrounding the openings are so connected together that when theplate is embedded in the vulcanite any bending of the latter will resultonly in a bending of the material and not in an opening out or expansionof same. The material or fabric for this purpose is stamped from a sheetof suitable material, so that the meshes [6 or Serial No. 179,272. Nomodel.)

portions surrounding the openings are dished concavo-convex in section,as best seen in Fig. 3, (whereby a better holding effectis obtained inthe vulcanite,) and are provided with an inclosingedge or wall 7), Fig.1, similarly dished, which binds the whole together and prevents anypart expanding or opening when bent, though it does not prevent thematerial from being easily bent by the fingers to the desired shape orcurvature.

In the instance of an upper case the piece is exteriorly suitably shapedto the palate and may carry by the edge or wall 6, if desired, a seriesof projecting lugs c, which can be bent into the spaces between theteeth or bent up into the vulcanite for holding purposes.

The openings inside the meshes are preferably polygonal in shape in thisform to afford a better hold to the vulcanite.

For the purposes of a lower case, Figs. 4:, 5, 6, 7, a strip (Z of thematerial above described is employed in such a form that its outsideedges g present a continuous line, whereby the desired efiect underexpansion or contraction is obtained. Such a strip is backed by a rod ofmetal c, which for lightness and strength and for its holding efiect onthe vulcanite is formed of a T shape in the form illustrated, or it maybe a channel or other like section, and which, together with thematerial (Z, can be bent into the desired shape. The rod of metal may bea continuous one, the rib being soldered or secured to the under side ofthe strip (Z at the points it touches the meshes; but I prefer to outsuch rib away, as at f, Fig. 6, to lighten it and also to provide moresurface for the vulcanite to penetrate into.

In both cases the mesh material or strip when embedded in the vulcanitewill present its widest faces to the line of least resistance throughthe latter, whereby they will have less tendency to work through samewhen bending of the vulcanite takes place, and this effect is greatlyassisted bythe concavo-convex character of same.

The strengtheners are placed in the vulcanite upper or lower casesduring the manufacture and may either be completely embedded therein or,if of suitable metal, may be embedded only flush with the surface and bepolished with the vulcanite.

'I am aware that metal gauze isv at present used for the purpose ofstrengthening upper cases; but by reason of its not being containedwithin a single binding line or edge its thickness has to be greaterthan a strengthening device of a similar size constructed according tomy invention. I am also aware that a filigree metal device or corrugatedwire applied to a bar is used for lower cases and without a bar forupper cases; but such filigree work or the like has no continuousbindingline and presents not only the disadvantages of expansion I haveabove referred to, but is arranged edgewise to the line of leastresistance-a point which it is my object to avoid.

hat 1 claim is 1. A strengthener for vulcanite artificialteeth basescomprising a metallic plate perforated with openings, and having 'acontinuous metallic edge surrounding, inclosing, and forming a part ofsaid perforated plate, and a number of metallic tongues forming part of,and projecting outwardly from, said surrounding edge.

2. A strengthener for Vulcanite artificialteeth bases comprising ametallic plate having open perforations, the Walls of which form asurrounding continuous edge concavo-convex in section, presenting itswidest face to the line of least resistance through the vulcanite, and abacking-rod secured thereto.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

ROBERT WALKER. WVitnesses:

ALLEN PARRY JoNEs, ARTHUR H. ALFORD.

